Hitachi Universal Storage Platform VM User Manual
Page 61
Functional and Operational Characteristics
3-17
Hitachi Universal Storage Platform V/VM User and Reference Guide
Mode
Category
Function
Default
MCU/RCU
491 ShadowImage
ShadowImage for
z/OS
FlashCopy V1
Improve the performance of ShadowImage, ShadowImage for
z/OS, and FlashCopy version 1.
Mode 491 = ON: The option (Reserve 05) of SI/SIz is
available. When this option is set to ON, copy operations (SI,
SIz, FCv1) are increased from 64 processes to 128 processes
for improved performance.
Mode 491 = OFF: The option (Reserve 05) of SI/SIz is not
available. The copy operations (SI, SIz, FCv1) are performed
with 64 processes.
Note:
Mode 491 requires at least three BED features. If there are
less than three BED features, mode 491 is not effective.
Enable mode 491 when the performance of ShadowImage,
ShadowImage for z/OS, and/or is considered to be
important.
Do not enable mode 491 when host I/O performance is
considered to be important.
When mode 491 is ON, set mode 467 to OFF. If mode 467
is ON, the performance may not improve.
OFF –
493 Mainframe
The CUIR function requires that the SA_ID reported to the
host is unique. The SA_ID value cannot be changed during
online operations. To change the SA_ID value from normal to
unique, set mode 493 to ON and then perform a power
cycle*. Setting mode 493 to ON without performing a power
cycle does not enable the function.
*Power cycle includes PS-OFF/ON (volatile/non-volatile),
start-up after breaker OFF/ON, or offline micro-program
exchange.
Mode 493 = ON: When mode 493 is ON and a power cycle is
performed, a unique SA_ID value for each port is reported to
the host.
Mode 493 = OFF: When mode 493 is OFF and a power cycle is
performed, and 2107 port is not set, normal SA_ID values are
reported to the host. When 2107 emulation is set, the SA_ID
value of mainframe PCB port remains unique even after
setting mode 493 to OFF and then performing a power cycle.
Caution: Power cycle is required.
OFF –
494
Mainframe
Enables CUIR processing when replacing a FICON PCB.
Mode 494 = ON: CUIR processing is available when replacing
a FICON PCB, but only when mode 493 is ON and a power
cycle* is performed to enable the SA_ID unique mode.
*Power cycle includes PS-OFF/ON (volatile/non-volatile),
start-up after breaker OFF/ON, or offline micro-program
exchange.
Mode 494 = OFF: CUIR processing is not available.
Caution: Power cycle is required.
OFF –